package org.mashart.pink.m.store;

import java.util.Hashtable;
import java.util.Enumeration;
import javax.microedition.rms.RecordStore;
import javax.microedition.rms.RecordEnumeration;
import javax.microedition.rms.RecordStoreException;

public class Preferences {

    private static Preferences unique;

    private String mRecordStoreName;

    private Hashtable mHashtable;

    private Preferences() {
        mRecordStoreName = "preferences";
        mHashtable = new Hashtable();
        load();
  }

    /**
     * Factory method
     * @return a unique instance of <code>Preferences</code>.
     */
    public static synchronized Preferences getInstance(){
        if(unique == null){
            unique = new Preferences();
        }
        return unique;
    }

  public String get(String key) {
    return (String)mHashtable.get(key);
  }

  public void put(String key, String value) {
    if (value == null) value = "";
    mHashtable.put(key, value);
  }

  private void load() {
    RecordStore rs = null;
    RecordEnumeration re = null;

    try {
      rs = RecordStore.openRecordStore(mRecordStoreName, true);
      re = rs.enumerateRecords(null, null, false);
      while (re.hasNextElement()) {
        byte[] raw = re.nextRecord();
        String pref = new String(raw);
        // Parse out the name.
        int index = pref.indexOf('|');
        String name = pref.substring(0, index);
        String value = pref.substring(index + 1);
        put(name, value);
      }
    }
    catch(RecordStoreException rse){
        rse.printStackTrace();
    }
    finally {
      if (re != null) re.destroy();
      try{
        if (rs != null) rs.closeRecordStore();
      }catch(RecordStoreException rse){
          rse.printStackTrace();
      }
    }
  }

  public void save() {
    RecordStore rs = null;
    RecordEnumeration re = null;
    try {
      rs = RecordStore.openRecordStore(mRecordStoreName, true);
      re = rs.enumerateRecords(null, null, false);

      // First remove all records, a little clumsy.
      while (re.hasNextElement()) {
        int id = re.nextRecordId();
        rs.deleteRecord(id);
      }

      // Now save the preferences records.
      Enumeration keys = mHashtable.keys();
      while (keys.hasMoreElements()) {
        String key = (String)keys.nextElement();
        String value = get(key);
        String pref = key + "|" + value;
        byte[] raw = pref.getBytes();
        rs.addRecord(raw, 0, raw.length);
      }
    }
    catch(RecordStoreException rse){
        rse.printStackTrace();
    }
    finally {
      if (re != null) re.destroy();
      try{
        if (rs != null) rs.closeRecordStore();
      }catch(RecordStoreException rse){
          rse.printStackTrace();
      }
    }
  }
}
